1. Field of the Invention
The present invention relates to a method of applying an ink-repellent film on the surface of a nozzle plate of an ink jet head and the nozzle plate on the surface of which is provided with the ink-repellent film.
2. Description of the Related Art
There is such a tendency that when an ink wet area appears around a nozzle on the surface of a nozzle plate, direct advance of ink drops becomes impaired, and when wetness becomes more remarkable, ink drops do not fly. As a countermeasure, such a technology that an ink-repellent film made of fluororesin or the like having high water repellency is provided on the surface of a nozzle plate to suppress the appearance of a wet area is proposed (for example, see Japanese Patent Application Laid-Open No. 2005-289039). According to such technology, the ink-repellent film is formed by applying an ink-repellent material onto the surface of the nozzle plate in accordance with a coating method such as screen method and spin coat method, and then, curing the ink-repellent material applied.
However, when the ink-repellent material gets into the interior of the nozzle while the ink-repellent material is applied, it results in a cause for impairing the direct advance of ink drops.
On the other hand, the ink-repellent film once it has got into the interior of the nozzle has high chemical resistance so that it is difficult to remove the ink-repellent film by applying a usual solvent. Thus, the ink-repellent film once it has got into the interior of the nozzle has been removed by the use of laser trimming and the like techniques.
However, when the laser trimming is applied, the surface of the nozzle interior coarsens, and further, there is such a tendency that the direct advance of ink drops is impaired due to remaining dust. As a result, there is a problem of deterioration in printing quality.
Under the circumstances, it is demanded to propose a method of applying an ink-repellent film by which invasion of an ink-repellent material into a nozzle can be prevented as well as a nozzle plate on which the ink-repellent film has been provided in accordance with the above-described applying method.